After AT&T had abandoned its unlimited data offering just before the launch of the iPhone 4, the carrier allowed customers already on the unlimited offering to retain their plans while offering new tiered plans to new subscribers. At the time, AT&T just cautioned that it would begin to throttle users who were in the top 5% of data consumers on unlimited plans that it would begin throttling, but it was never clear what the cut off would be before throttling would occur. Now, it seems that throttling will begin after 2 GB.
One subscriber, John Cozen, who was on the grandfathered unlimited data plan received notice from AT&T regarding usage and throttling. After receiving notice, Cozen checked his iPhone and he found out that he had just used 2.1 GB for the month. Essentially, it seems that AT&T is sending out notices to customers on grandfathered unlimited plans after they reach 2 GB of usage in the month.
While customers who use more than 2 GB on the unlimited plan won’t be subjected to overage charges, those customers would experience degraded data speeds, from 3G or 4G speeds down to 2G EDGE speeds.
The practice of throttling is most common on T-Mobile USA and it seems that throttling will remain a contention as customers use more data thanks to enhanced technology, smarter apps, and increased smartphone adoption.
Though no overages are assessed, unlimited customers may be left feeling like AT&T pulled a fast one on them. While the grandfathered plan costs $30, newer $30 plans offer 3 GB of data. That means grandfathered users are given 2 GB of data per month at 3G or 4G speeds before throttling occurs and newer plans offer customers 3 GB of data and overages are assessed after a customer reaches 3 GB.